London's FTSE 100 Index closed at all-time high after investors were cheered by a deal to extend Greece's bail-out terms.

The breakthrough came after European creditors approved the list of reform measures being proposed by Athens as a requirement of the country's four-month extension to its debt arrangements

This led the FTSE 100 Index to close up 37.5 points to 6949.6, breaking the London's top flight's high of 6930 set in December 1999.

The blue chip index also broke the highest intra-day record hitting 6958.9, which beat 6950 also set 15 years ago.

Fidelity Worldwide Investment investment director Tom Stevenson said: "This is a watershed moment. Investors have finally exorcised the ghost of the dot.com bubble which has haunted the market for a decade and a half."

The Greece reform plans, which include measures to deal with tax evasion and corruption, have received a favourable response from institutions such as the International Monetary Fund as well as in the markets.

A rise in the price of Brent crude oil to about 60 US dollars was another factor in boosting the London market.

The outlook for interest rate hikes in the US also occupied investors during an otherwise quiet session for corporate news.

Federal Reserve chair Janet Yellen told Congress today that the central bank is unlikely to hike interest rates for at least the next two meetings because US wage growth remains sluggish.

The news provided traders with welcome certainty and meant the pound was slightly lower against the US dollar at 1.54 and flat versus the euro at 1.36.

The biggest rise in the FTSE 100 Index came from BHP Billiton after the mining giant reported a smaller than expected 31% drop in half-year profits.

The blue-chip giant also impressed investors with its plans for spending cuts at a time of tumbling commodity prices.

Shares lifted 6% or 96.5p to 1643.5p, with rival Glencore up almost 3% or 8.3p to 295.4p.

In other corporate news, shares in housebuilder Persimmon were sharply lower despite the company reporting a 44% rise in annual profits.

Persimmon said the market returned to more balanced conditions in the second half of 2014 and that it had made an encouraging start to 2015 with current total forward sales of £1.49 billion, 5% ahead of the previous year.

This failed to impress investors as shares dived by more than 3% or 60p to 1650p. Rival companies were also impacted, with Taylor Wimpey off 3.8p to 141.5p and Bovis Homes down 14.5p to 936.5p.

There was also a mixed response to results from automotive engineering firm GKN, which posted a 4% rise in underlying annual profits to £601 million.

Shares fell 12.4p to 373.6p as Cantor Fitzgerald broker Andy Chambers said the outlook for the current year "errs on the side of caution."

The biggest risers on the FTSE 100 Index were BHP Billiton up 96.5p at 1643.5p, Anglo American up 39p at 1237p, Fresnillo up 24.5p at 827p and Antofagasta up 22p at 754.5p.

The biggest fallers on the FTSE 100 Index were Meggitt down 34p at 537p, Persimmon down 60p at 1650p, GKN down 12.4p at 373.6p and Vodafone down 6.2p at 226.5p.